Adjustable earpiece for receivers



Nov. 14, 1950 D. w. MARTIN 2,529,562

ADJUSTABLE EARPIECE FOR RECEIVERS Filed Jan. 2, 1947 INVENTOR .5A/wa Wfl/427W BY 69M ATTORNEY Patented Nov. 14, i950 UNITED STATES PATENT o-EFl-CE Daniel W. Martin, Blackwood, N. J.,`assig,nor to Radio Corporation of America, a corporation of Delaware Application January 2, 1947,` Serial-No.)119;651`

13 Claims.A (Cl.`179- 182) This invention. relates to telephone receivers of the type that are worn. on the head and are commonly referred to. as ,headset receivers, and more particularly. to .an earcap for use on such receivers. A

Headset; telephone receivers areA frequently used in locations where surrounding noise is at a high level, as 'in battleships, airplanes, -and the like. When the/external noises` are loud, the signal to .noise ratio is correspondingly low and it becomes difficultto hear the signals clearly. To avoid this 4vcondition, various types of earcaps have been. proposed heretofore for use on receiver units for. the purpose of sealing the ears of the user against external noise. However, such earcaps have not proven satisfactory for one reason or another.

The primary object ofi my present invention is to provide, in a headset telephone unit, an improved earcap which Willreiectively seal off external noises when appliedto .the ear so that the signal to noise .ratio will be maintained quite high.

More particularly, Vit is an objectof my present invention to provide van improved earcap -for headset receivers by means lof which a great reduction in external noiseV will be obtained and thereby theY sensitivity `and low .frequency response of the receivers will be greatly improved.

Another object of my present invention is to provide an improved earcap for headset receivers which will effectively acoustically seal against external noises not only the outer ear but also the auditory canal .of the ear at the point of maximum flare in the auditory canal cross section.

Still another object of my present invention is to provide an improved earcap-as aforesaid which may be made in one size and shape and yet Will accuratelyt ears-ofA various sizes. Y

A further object 'of 'my `present' invention `is to provide'an improved earcap as aforesaid which can be worn with great comfort by the user.

vStill a further object of my present 'invention is to provide an improved earcap as above set forth which can be applied to the .ear quickly and accurately and `which is not apt feto become dislodged easily to a position where it will be .ineffective toseal the ear againstexternal noises.

It is also an object Yof my present invention-to provide an improved earc'ap for headset-receivers which is simple in construction, inexpensive in cost, `and highlyeefcient in use.

In accordance with one Aform of my present invention, the yearcap comprises a pad .of soft rubber, -suchas .sponge rubber,v constructed to be mounted on. the Vcasing of a headset receiver and adapted to ybe placed against the outer por-l tion o f the ear to provide an external acoustical sealtherefor. The. Ipad has `a central opening and it is provided over said opening with a tubular .member which extends therefrom and which preferablyter-minates in a flange .adapted to seat against the auditory canal of the ear at vthe entrance thereof (that is, where the auditory canal lis of maximum flare lin cross section) to thereby provide an internal acoustical seal for the ear. The tubular member is preferably made 0f fairly thin, soft rubber and -is .disposed with its axis angularly related to the axis of the aforementionedv pad, the angle being such that, when the pad is applied to the ear, the tubular member will extend tothe auditory canal at the proper angle. l

The aforementioned tubular member is formed Withone or more circumferential accordion pleats whereby it is collapsible and expansible along its own axis for accomodation to ears of different sizes. Since, the tubular member is made of thin rubber and is, therefore, flexible, it is capable of Ilexing or bending in all planes passing through its axis. To prevent this tubular member from so bending When it is applied to `the ear, I provide Within ita ,pair lof rigid, telescopically .arranged tubes one of which Aslides within the other as the tubular member .expands or contracts. The telescopic arrangement of the tubes permits free .collapse and expansion of the tubular sealing member while at the same time preventing bending of .this member. In this way, the `angular .relation between the axis of the tubular extension on-.the ear pad and the axis of the ear pad itself or the` vibratory diaphragm forming part of .the ytransducer unit in conventional telephone .receivers is maintained constant. At th-e same time, however, lthe tubular sealing member is free to Vbeladjusted and to `accommo- V.date itself to lears :of different sizes wherebya good seal can be Yobtained .for the ear.

The novel featuresthat I consider `characteristic of my invention, both .as toits. organization and method of operation, as well .as additional objects and 4advantages thereof, will. better be understood fromthe following description of one embodiment thereof when ,read in connection with the accompanying drawing in which Figure -l is-.a centralsectional View of a telephone receiver With...an earcap according to my Ypresent inventionapplied.thereto and with the tubular member which. .acts as a seal against 3 the auditory canal shown in fully expanded position,

Figure 2 is a fragmentary sectional view of my improved earcap showing the aforesaid tubular member in contracted or collapsed condition such as it would occupy when applied to the ear,

Figure 3 is an enlarged, central, longitudinal, sectional View of the telescopically arranged tubes within the aforesaid tubular sealing member and which maintain this member against flexure or bending in planes containing the axis thereof,

Figure 4 is a sectional View taken on the plane of the line IV-IV of Figure 3, and

Figure 5 is a top plan view showing a headset comprising a pair of receiver units provided with my improved earcap applied to the head of the user.

Referring more particularly to the drawing wherein similar reference characters designate corresponding parts throughout, there is shown, in Figure l, a telephone receiver having a casing I within which is housed an electro-acoustical transducer 3 of any suitable type. The transducer l3 may be a sound powered telephone unit, for example, operating in well known manner and having a diaphragm 5 which generates acoustical waves during vibration thereof. A guard plate 1 having a perforated, central extension 9 serves to protect the diaphragm 5, the perforations in the extension 9 serving yto permit passage of sound waves generated by the diaphragm 5.

Fitted around the marginal portions of the casing I and the guard plate 1 is an ear pad II which may be molded out of sponge'rubber or .other suitable, soft material. The pad II Yis adapted to be placed against the outer ear I3'of a user, as shown in Figure 5, to provide an external acoustical seal against sounds in the ambient. If desired, the pad II may be made hollow to provide a'chamber I5 which communicates with the outside air through a, plurality of vopenings I1. This provides an air cushion for the pad II and helps to insure a snug flt of the pad against the ear whereby both comfort to the wearer and a good seal against external sounds are assured.

The pad II is provided with a tubular extension I9 which ts around the guard plate extension 9 and extends in a direction such that its axis is angularly related to the common axis of the pad itself and of the diaphragm 5 for a purpose to be presently set forth. The extension I9 v`is formed with an annular slot 2I in which is vided With a flange 3l which seats in an'lannular slot 33 of a tubular member 35 made of fairly soft rubber and therefore quite flexible. v The tubular member 35 is held in place against the ear pad extension I9 in extension thereof by having its base flange 36 clamped firmly between the insert 25 and the flange 3I of the tube 21. The member 35 terminates in a flange 31 adjacent to which it is formed with an annular slot 39 in which is seated a flange 4I on the inner tube 29.

It will be noted that the ilexible, tubular member 35, the two rigid, telescopically arranged tubes 21 and 29, and the ear ,pad extension I9 are all arranged on a common axiswhich is angularly related to the common axis of the lear pad proper and thev diaphra'gm`5; This angular relation is such that, when the receiver is applied to the ear, the tubular member 35 will extend in the direction of (that is, substantially coaxially with) the auditory canal of the ear, and the flange 31 will t snugly against this canal at the point of maximum flare thereof in cross -section (that is, at the entrance thereto) to thereby provide an internal acousticaljsealfor the ear. The combined action of the pad I I- andthe flange 31 effectively seals the ear against troublesome outside noises which may be encountered and therefore not only enhances the low frequency response of the receiver but also improves the sensitivity thereof.

Since the earsv of different individuals vary in size, some provision must be made to insure a snug fit of the flange 31 against the auditory canal entrance. For this purpose, the tubular member 35 is formed with one or more circumferential, accordion pleats 43 by reason of which it is axially compliant and therefore collapsible in an axial direction from its normally fully extended position of Fig. 1 to its contracted position of Fig. 2, and vice versa. A pair of diametrie cally opposed lugs 45 on the tube 29 which ride in longitudinal slots 41 in the tube 21 limit the outward movement ofthe tube 29 relative to the tube 21 by engagement with the upperend 49k of, the tube 29 to thereby limit theamount or extent of expansion of the tubular member 35.V Engagementvr of the portion of the member 35 under the flange 4I with the end 49 of the outer tube 21 may be availed of to limit the amount of collapse of the tubular member 35, if necessary. The collapse and expansionv of the member 35 is permittedfby reason of the. telescopic actionof the tubes 21 and 29. At the'same time, since the tubes 21 and 29 are rigid, they maintain the flexible, tubular member 35 against ilexure or bending in planes containing its axis. In this way, the angular relation between the axis of the tubular member 35 and the axis of the ear pad II and the diaphragm 5 is maintained vconstant and a proper fit of the flange 31 against the auditory canal entrance is further assured'.

A pair of receivers with earcaps such as described above may be mounted on a headband consisting of two, close-fitting metallic bands 5I which are adapted to fit over. the head, as shown in Fig. 5. Preferably, the headbands 5I are arranged so that they join at the sides just in front of the ears, where metal strips or links 53 connect the bands 5I with the receivers. As the receivers are placed on the ears, the headband construction causes the receivers to turn easily in such a direction as to help the flanges 31,:0f the earcaps to seat properly against the auditory canal entrances while at the .Sametime causing the ear pads II to tsnugly against the'ears.Av

Although I have shown andk described only a single embodiment of my present invention, it

"against the outer portion of the ear Yto provide an' external acoustical seal therefor, said'. pad having aY chamber therein adapted to receive a Ntelephone receiver, and a pleated tubularmem- 'ber extending from said pad'and terminating-ih amaze:

ai'ree'ly disposed end, saidtubular member 'coind mun'icatin'gA with saidV chamber to' provide 1a lpassage-for'sound waves emanating from the'telephone receiver, said freely disposed end being of'a size to seat against the auditory canal of the ear at the entrance thereof to provide an internal acoustical seal for the ear, said pleated tubular member including means whereby it is longitudinally compliant for adjustment in an axial direction for accommodation to ears of different sizes. t Y

"r2, inearcap for headset telephone receivers Which comprises a pad adapted to be placed against the outer portion of the ear to provide an external acoustical seal therefor, said pad having a chamber therein adapted to receive a telephone receiver, and a pleatedtubularmember extending from said `pad and terminating in a `freely disposed end, said tubular-member communicating with said chamber toprovidea passage for sound Waves emanatingl Vfrom the telephone receiver, said freely disposed end being of" la size Ato seat against the auditorycanal of the ear at the entrance thereof to provide an internal acoustical seal for the ear, said pleated tubular member also being disposed with its axis angularly related to the axis of said pad and including means whereby it is longitudinally compliant for adjustment along its own axis for accommodation to ears of different sizes.

3. An earcap for headset telephone receivers which comprises a pad adapted to be placed against the outer portion of the ear to provide an external acoustical seal therefor, said pad having a chamber therein adapted to receive a telephone receiver, and a pleated tubular member extending from said pad in a direction such that its axis is angular-ly related to that of said pad, said pleated tubular member communicating with said chamber to provide a passage for sound waves emanating from the telephone receiver and terminating in a flange adapted to seat against the auditory canal of the ear at the entrance thereof to provide an internal acoustical seal for the ear and including means whereby it is longitudinally compliant for adjustment along its own axis for accommodation to ears of different sizes.

4. An earcap for headset telephone receivers which comprises a pad adapted to be placed against the outer portion of the ear to provide an external acoustical seal therefor, said pad having a chamber therein adapted to receive a telephone receiver, and a tubular member extending from said pad and terminating in a freely disposed end, said tubular member communicating with said chamber to provide a passage for sound waves emanating from the telephone receiver, said freely disposed end being of a size to seat against the auditory canal of the ear at the entrance thereof to provide an internal acoustical seal for the ear, said tubular member also being disposed with its axis langularly related to the axis of said pad and having means including at least one accordion pleat circumferentially thereof whereby said tubular member is collapsible and expansible along its own axis for accommodation to ears of i rurth'erfby the addition of: 'means .in association with said tubular. member for.` maintaining' said furtherV by the addition of Aa plurality of teles-i` copically arranged,rrigid tubes within said tubular member. for maintaining saidmember against' flexur'etin said planes, said tubes being telescopic to permit collapse. and expansion of said mem ber along its axis. -i v8An earcap according to claim 4 character# ized infthatsaid tubular member is itself exible in planes :containing its axis, characterizedfur'- ther V'by the laddition of a plurality of telescopically arranged, rigid tubes withinfsaid tubular member for 'maintaining said member against exure `in said planes, .said tubes being telescopic to permit collapse and expansion of said member alongits axis vandincluding means for limiting the telescopicV action thereof whereby to limit the amount of lcollapse and expansion of said tubular member. S9. An earcap for headset telephone receivers which. comprises a pad adapted to be placed against the outer portion of the ear to provide an external acoustical seal therefor, said paid having a chamber therein adapted to receive a telephone receiver, a tubular member extending from said pad and terminating in a freely disposed end, said tubular member communicating with said chamber to provide a passage for sound waves emanating from the telephone receiver, said freely disposed end being of a size to seat against the auditory canal of the ear at the entrance thereof to provide an internal acoustical seal for the ear, said tubular member being compliant Whereby it is normally freeto flex in planes containing its longitudinal axis and being formed With accordion pleats circumferentially thereof whereby it is collapsible and expansible along its axis for accommodation to ears of different sizes, and a plurality of telescopically arranged, rigid tubes within said tubular member for maintaining said member against flexure in said planes while permitting collapse and expansion of said member by reason of their telescopic arrangement.

10. An earcap for headset telephone receivers which comprises a pad adapted to be placed against the outer portion of the ear to provide an external acoustical seal therefor, said pad having a chamber therein adapted to receive a telephone receiver, a tubular member extending from said pad and communicating with said chamber to provide a passage for sound waves emanating from the telephone receiver, said tubular member terminating in a flange adapted to seat against the auditory canal of the ear at the entrance thereof to provide an internal acoustical seal for the ear, said tubular member also being made of iiexible material whereby it is normally free to ex in planes containing its longitudinal axis and being formed with accordion pleats circumferentially thereof whereby it is collapsible and expansible along its axis for accommodation to ears of different sizes, and a plurality of telescopically arranged, rigid tubes within said tubular member for maintaining said member against exure in said planes while permitting collapse and expansion of said member by reason of their telescopic arrangement.

11. In a headset telephone receiver having a casing, and an electro-acoustical transducer within said casing including a vibratory diaphragm, an earcap for the telephone receiver adapted to be mounted on the casing over .the diaphragm, said earcap comprising (1)' a pad adapted to be placedagainst the outer portion of;

the ear to provide an external acoustical seal therefor, said pad having a chamber therein adapted to receive a telephone receiver, and (2) a tubular member extending from said padY 'and terminating in a freely disposed end, said tubular member communicating with said chamber to provide a passage for sound waves emanating from the telephone receiver, said freely disposed end being of a size to seat against the auditory canal of the ear at the entrance thereof to provide an internal acoustical seallfor the ear, said tubular memberv having communication with said chamber for transmission to the auditory canal of the acoustical Waves produced by said diaphragm during vibration thereof and having meansincluding at least one accordion pleat circumferentially thereof whereby said tubular member is collapsible and eXpansible for accom-l modation to ears of different sizes Without affectingts communication with said diaphragm.

12. The invention set forth in claim 11 characterized in that the axis ofV said tubular member is angularly related to the axis of said diaphragm.

13. The invention set forthv in claim 11 char-` acterized inr that the axis of said tubular mem-` ber is angularly related to the axis of said diaphragm, and characterized further by the addition of means in association with said tubular member for maintaining said angular relation constant. Y

' DANIEL W. MARTIN.

REFERENCES CITED The following references are of record in the leoi this patent:

UNITED STATES PATENTS p Date Number Name l 572,108 Farrington Dec. 1, 18,96 A1,623,552 Pollard Apr. 5, 1927 1,624,144 Mathieu Apr. 12, 1927,- 1,677,1185 Kaisling July 17, 1928 2,337,953 Wirsching Dec. 28, 1943 2,353,070 Y Pitkin July 4, 1944 2,430,229 Kelsey Nov. 4, 1947 Valentine Aug. 17, 1948 

